1. Field of the Invention
The present invention relates to a reclining device for a vehicle seat.
2. Description of the Prior Art
Disclosed in Japanese Patent Publication Nos. 63(1988)-65327 and 3(1991)-52965 is a reclining device which includes a first arm member fixed to one side of a frame structure of a seat cushion, a second arm member fixed to one side of a frame structure of a back rest and connected with the first arm member by means of a hinge pin for relative rotation about the hinge pin, the second arm member being formed with an internal tooth portion concentrical with the hinge pin, a slide pawl slidably supported on the first arm member to be moved in a radial direction with respect to the hinge pin for engagement with the internal tooth portion of the second arm member, and a cam element rotatably mounted on the hinge pin to move the slide pawl toward and away from the internal tooth portion of the second arm member.
In such a conventional reclining device as described above, the cam element is slightly moved by a rotational force applied to the second arm since the first and second arm members are connected with each other through the cam element.
Further, the first and second arm members are connected with each other through the cam element. This causes unwanted movement of the slide pawl, resulting in unexpected disengagement of the slide pawl from the internal tooth portion of the second arm member. Moreover, if the internal tooth portion of the second arm member is formed smaller in its pitch diameter to provide the reclining device in a small size, the cam element becomes small in size, resulting in a decrease in the connecting strength of the first and second arm members.